1 .TH g_dipoles 1 "Thu 16 Oct 2008"
3 g_dipoles - computes the total dipole plus fluctuations
8 .BI "-enx" " ener.edr "
10 .BI "-s" " topol.tpr "
11 .BI "-n" " index.ndx "
13 .BI "-eps" " epsilon.xvg "
15 .BI "-d" " dipdist.xvg "
16 .BI "-c" " dipcorr.xvg "
18 .BI "-adip" " adip.xvg "
19 .BI "-dip3d" " dip3d.xvg "
20 .BI "-cos" " cosaver.xvg "
21 .BI "-cmap" " cmap.xpm "
22 .BI "-q" " quadrupole.xvg "
23 .BI "-slab" " slab.xvg "
33 .BI "-epsilonRF" " real "
39 .BI "-axis" " string "
41 .BI "-gkratom" " int "
42 .BI "-gkratom2" " int "
45 .BI "-nlevels" " int "
46 .BI "-ndegrees" " int "
48 .BI "-[no]normalize" ""
52 .BI "-beginfit" " real "
53 .BI "-endfit" " real "
55 g_dipoles computes the total dipole plus fluctuations of a simulation
56 system. From this you can compute e.g. the dielectric constant for
58 For molecules with a net charge, the net charge is subtracted at
59 center of mass of the molecule.
62 The file Mtot.xvg contains the total dipole moment of a frame, the
63 components as well as the norm of the vector.
64 The file aver.xvg contains |Mu|2 and |Mu| 2 during the
66 The file dipdist.xvg contains the distribution of dipole moments during
68 The mu_max is used as the highest value in the distribution graph.
71 Furthermore the dipole autocorrelation function will be computed when
72 option -corr is used. The output file name is given with the
76 The correlation functions can be averaged over all molecules
79 ), plotted per molecule seperately (
82 or it can be computed over the total dipole moment of the simulation box
90 produces a plot of the distance dependent Kirkwood
91 G-factor, as well as the average cosine of the angle between the dipoles
92 as a function of the distance. The plot also includes gOO and hOO
93 according to Nymand & Linse, JCP 112 (2000) pp 6386-6395. In the same plot
94 we also include the energy per scale computed by taking the inner product of
95 the dipoles divided by the distance to the third power.
104 g_dipoles -corr mol -P1 -o dip_sqr -mu 2.273 -mumax 5.0 -nofft
107 This will calculate the autocorrelation function of the molecular
108 dipoles using a first order Legendre polynomial of the angle of the
109 dipole vector and itself a time t later. For this calculation 1001
110 frames will be used. Further the dielectric constant will be calculated
111 using an epsilonRF of infinity (default), temperature of 300 K (default) and
112 an average dipole moment of the molecule of 2.273 (SPC). For the
113 distribution function a maximum of 5.0 will be used.
115 .BI "-enx" " ener.edr"
121 Trajectory: xtc trr trj gro g96 pdb cpt
123 .BI "-s" " topol.tpr"
125 Run input file: tpr tpb tpa
127 .BI "-n" " index.ndx"
135 .BI "-eps" " epsilon.xvg"
143 .BI "-d" " dipdist.xvg"
147 .BI "-c" " dipcorr.xvg"
155 .BI "-adip" " adip.xvg"
159 .BI "-dip3d" " dip3d.xvg"
163 .BI "-cos" " cosaver.xvg"
167 .BI "-cmap" " cmap.xpm"
169 X PixMap compatible matrix file
171 .BI "-q" " quadrupole.xvg"
175 .BI "-slab" " slab.xvg"
181 Print help info and quit
183 .BI "-nice" " int" " 19"
186 .BI "-b" " time" " 0 "
187 First frame (ps) to read from trajectory
189 .BI "-e" " time" " 0 "
190 Last frame (ps) to read from trajectory
192 .BI "-dt" " time" " 0 "
193 Only use frame when t MOD dt = first time (ps)
196 View output xvg, xpm, eps and pdb files
198 .BI "-[no]xvgr" "yes "
199 Add specific codes (legends etc.) in the output xvg files for the xmgrace program
201 .BI "-mu" " real" " -1 "
202 dipole of a single molecule (in Debye)
204 .BI "-mumax" " real" " 5 "
205 max dipole in Debye (for histrogram)
207 .BI "-epsilonRF" " real" " 0 "
208 epsilon of the reaction field used during the simulation, needed for dieclectric constant calculation. WARNING: 0.0 means infinity (default)
210 .BI "-skip" " int" " 0"
211 Skip steps in the output (but not in the computations)
213 .BI "-temp" " real" " 300 "
214 Average temperature of the simulation (needed for dielectric constant calculation)
216 .BI "-corr" " enum" " none"
217 Correlation function to calculate:
227 .BI "-[no]pairs" "yes "
228 Calculate |cos theta| between all pairs of molecules. May be slow
230 .BI "-ncos" " int" " 1"
231 Must be 1 or 2. Determines whether the cos is computed between all mole cules in one group, or between molecules in two different groups. This turns on the -gkr flag.
233 .BI "-axis" " string" " Z"
234 Take the normal on the computational box in direction X, Y or Z.
236 .BI "-sl" " int" " 10"
237 Divide the box in nr slices.
239 .BI "-gkratom" " int" " 0"
240 Use the n-th atom of a molecule (starting from 1) to calculate the distance between molecules rather than the center of charge (when 0) in the calculation of distance dependent Kirkwood factors
242 .BI "-gkratom2" " int" " 0"
243 Same as previous option in case ncos = 2, i.e. dipole interaction between two groups of molecules
245 .BI "-rcmax" " real" " 0 "
246 Maximum distance to use in the dipole orientation distribution (with ncos == 2). If zero, a criterium based on the box length will be used.
249 Plot the 'torsion angle' defined as the rotation of the two dipole vectors around the distance vector between the two molecules in the xpm file from the -cmap option. By default the cosine of the angle between the dipoles is plotted.
251 .BI "-nlevels" " int" " 20"
252 Number of colors in the cmap output
254 .BI "-ndegrees" " int" " 90"
255 Number of divisions on the y-axis in the camp output (for 180 degrees)
257 .BI "-acflen" " int" " -1"
258 Length of the ACF, default is half the number of frames
260 .BI "-[no]normalize" "yes "
263 .BI "-P" " enum" " 0"
264 Order of Legendre polynomial for ACF (0 indicates none):
274 .BI "-fitfn" " enum" " none"
293 .BI "-ncskip" " int" " 0"
294 Skip N points in the output file of correlation functions
296 .BI "-beginfit" " real" " 0 "
297 Time where to begin the exponential fit of the correlation function
299 .BI "-endfit" " real" " -1 "
300 Time where to end the exponential fit of the correlation function, -1 is till the end